1. Technical Field
This invention relates to coated refractory shapes such as those used in bottom pouring of ingots in ingot molds.
2. Description of the Prior Art
Prior devices and assemblies used in bottom pouring of ingots and cast shapes from molten metal have included various structures such as those seen in U.S. Pat. Nos. 3,604,598, 3,810,506, 3,929,184, 3,865,177, 4,111,254, 4,356,994, 4,452,296 and 4,506,813.
Typical arrangements of multiple mold bottom pouring are illustrated in the above U.S. Pat. Nos. 3,810,506 and 3,865,117 wherein a vertically standing fountain or trumpet is positioned adjacent one or more ingot molds or the like.
U.S. Pat. No. 3,604,598 adds electrical heating to a bottom pour-teeming vessel. U.S. Pat. No. 3,929,184 discloses the metal receiving and transferring fountain or trumpet formed of a plurality of refractory sections. U.S. Pat. No. 4,111,254 discloses the formation of a casting mold made of sheet metal embedded in a supporting mass of refractory particles. U.S. Pat. No. 4,356,994 discloses the units of a pouring system for a so-called uphill teeming as comprising an outer casing having an inner refractory liner and a refractory insulating material therebetween. U.S. Pat. No. 4,452,296 discloses an aluminum-diffusion coated steel pipe gating system which represents the fountain or trumpet of a bottom pour assembly including a mold. U.S. Pat. No. 4,506,813 discloses a fountain or a trumpet of a bottom pour arrangement formed of a refractory tube in a sheath with a body of particulate material between the refractory tube and the sheath.
The present invention eliminates the problems found in the prior art devices by forming the tiles or inserts which are sometimes termed a refractory lining in a fountain or a trumpet as refractory shapes having an inner coating of a graphite composition capable of penetrating the refractory surface to form a coating that resists flaking or parting of the refractory when subjected to molten metal by controlling the degree of heat transfer for a period of time sufficient to permit the refractory to adjust to the elevated temperature at a rate of expansion less than that resulting in flaking or parting of the refractory.